The present invention relates to a method for connecting an expansion module to a programmable electric switching device.
Such switching devices may include, for example, small control systems, control relays or the like. It is common to all switching devices that they have a processing unit, for example, in the form of a microprocessor, an integrated display unit as well as an integrated operating control unit.
A programmable control relay of this kind including integrated arithmetic, operating control and display units is already known from the main catalog “Automatisieren und Energie verteilen '99” [Automation and Power Distribution '99] (pages 05/006-05/007) of the Klöckner-Moeller GmbH Company. These devices are applicable for minor control tasks in the field of domestic installations as well as in the construction of control cabinets and in mechanical and apparatus engineering. In lieu of the conventional wiring technique of individual components such as auxiliary contactors, relays or counter modules, the desired functions are “wired” (programmed) in the control relay using software. The programming is preferably carried out in circuit diagram representation.
Moreover, programmable control systems (for example, compact control systems) are known which can be expanded in their functionality via so-called “expansion modules” (main catalog of Klöckner-Moeller GmbH Company; “Automatisieren und Energie verteilen '99” [Automation and Power Distribution '99] (pages 01/004-01/005).
Switching devices such as those described above are at present very limited in their expandability. If the intention is for a basic device to be expanded with an expansion module, it is required that the expansion module exist in kind of a “table including connectable expansion modules” in the current operating system of the basic device. The device, which is already known to the basic device, is then selected and thus added to the functionality of the basic device. To make these programmable switching devices such as programmable control systems, logic relays and the like compatible for future expansion modules, the application software and the specific operating system including the above mentioned table must be updated at the particular time. For this, new hardware and software drivers have to be developed. New expansion modules cannot be used until the control system has been updated.